Real-world range vs payload for electric delivery trucks?

I'm running a small delivery fleet and looking at electric box trucks. The advertised range always assumes no payload. Once you load up to 10k lbs, range seems to drop by 30-40%. Anyone have real data from operating e-trucks in city routes? Also, how are you handling depot charging with multiple vehicles? We're considering 25kW AC vs 150kW DC chargers. Cost